#define DEBUG_TYPE "pre-alloc-split"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
+#include "llvm/CodeGen/LiveStackAnalysis.h"
+#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
-#include <map>
using namespace llvm;
-STATISTIC(NumSplit , "Number of intervals split");
+static cl::opt<int> PreSplitLimit("pre-split-limit", cl::init(-1), cl::Hidden);
+
+STATISTIC(NumSplits, "Number of intervals split");
+STATISTIC(NumRemats, "Number of intervals split by rematerialization");
+STATISTIC(NumFolds, "Number of intervals split with spill folding");
+STATISTIC(NumRenumbers, "Number of intervals renumbered into new registers");
namespace {
class VISIBILITY_HIDDEN PreAllocSplitting : public MachineFunctionPass {
- MachineFunction *CurMF;
+ MachineFunction *CurrMF;
const TargetMachine *TM;
const TargetInstrInfo *TII;
MachineFrameInfo *MFI;
MachineRegisterInfo *MRI;
LiveIntervals *LIs;
+ LiveStacks *LSs;
// Barrier - Current barrier being processed.
MachineInstr *Barrier;
// CurrLI - Current live interval being split.
LiveInterval *CurrLI;
- // LIValNoSSMap - A map from live interval and val# pairs to spill slots.
- // This records what live interval's val# has been split and what spill
- // slot was used.
- std::map<std::pair<unsigned, unsigned>, int> LIValNoSSMap;
+ // CurrSLI - Current stack slot live interval.
+ LiveInterval *CurrSLI;
+
+ // CurrSValNo - Current val# for the stack slot live interval.
+ VNInfo *CurrSValNo;
+
+ // IntervalSSMap - A map from live interval to spill slots.
+ DenseMap<unsigned, int> IntervalSSMap;
- // RestoreMIs - All the restores inserted due to live interval splitting.
- SmallPtrSet<MachineInstr*, 8> RestoreMIs;
+ // Def2SpillMap - A map from a def instruction index to spill index.
+ DenseMap<unsigned, unsigned> Def2SpillMap;
public:
static char ID;
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<LiveIntervals>();
AU.addPreserved<LiveIntervals>();
+ AU.addRequired<LiveStacks>();
+ AU.addPreserved<LiveStacks>();
AU.addPreserved<RegisterCoalescer>();
if (StrongPHIElim)
AU.addPreservedID(StrongPHIEliminationID);
else
AU.addPreservedID(PHIEliminationID);
+ AU.addRequired<MachineDominatorTree>();
+ AU.addRequired<MachineLoopInfo>();
+ AU.addPreserved<MachineDominatorTree>();
+ AU.addPreserved<MachineLoopInfo>();
MachineFunctionPass::getAnalysisUsage(AU);
}
virtual void releaseMemory() {
- LIValNoSSMap.clear();
- RestoreMIs.clear();
+ IntervalSSMap.clear();
+ Def2SpillMap.clear();
}
virtual const char *getPassName() const {
unsigned&);
MachineBasicBlock::iterator
- findSpillPoint(MachineBasicBlock*, MachineInstr*,
+ findSpillPoint(MachineBasicBlock*, MachineInstr*, MachineInstr*,
SmallPtrSet<MachineInstr*, 4>&, unsigned&);
MachineBasicBlock::iterator
- findRestorePoint(MachineBasicBlock*, MachineInstr*,
+ findRestorePoint(MachineBasicBlock*, MachineInstr*, unsigned,
SmallPtrSet<MachineInstr*, 4>&, unsigned&);
- void RecordSplit(unsigned, unsigned, unsigned, int);
+ int CreateSpillStackSlot(unsigned, const TargetRegisterClass *);
- bool isAlreadySplit(unsigned, unsigned, int&);
+ bool IsAvailableInStack(MachineBasicBlock*, unsigned, unsigned, unsigned,
+ unsigned&, int&) const;
- void UpdateIntervalForSplit(VNInfo*, unsigned, unsigned);
+ void UpdateSpillSlotInterval(VNInfo*, unsigned, unsigned);
- bool ShrinkWrapToLastUse(MachineBasicBlock*,
+ VNInfo* UpdateRegisterInterval(VNInfo*, unsigned, unsigned);
+
+ bool ShrinkWrapToLastUse(MachineBasicBlock*, VNInfo*,
SmallVector<MachineOperand*, 4>&,
SmallPtrSet<MachineInstr*, 4>&);
bool SplitRegLiveInterval(LiveInterval*);
bool SplitRegLiveIntervals(const TargetRegisterClass **);
- };
+
+ void RepairLiveInterval(LiveInterval* CurrLI, VNInfo* ValNo,
+ MachineInstr* DefMI, unsigned RestoreIdx);
+
+ bool createsNewJoin(LiveRange* LR, MachineBasicBlock* DefMBB,
+ MachineBasicBlock* BarrierMBB);
+ bool Rematerialize(unsigned vreg, VNInfo* ValNo,
+ MachineInstr* DefMI,
+ MachineBasicBlock::iterator RestorePt,
+ unsigned RestoreIdx,
+ SmallPtrSet<MachineInstr*, 4>& RefsInMBB);
+ MachineInstr* FoldSpill(unsigned vreg, const TargetRegisterClass* RC,
+ MachineInstr* DefMI,
+ MachineInstr* Barrier,
+ MachineBasicBlock* MBB,
+ int& SS,
+ SmallPtrSet<MachineInstr*, 4>& RefsInMBB);
+ void RenumberValno(VNInfo* VN);
+ void ReconstructLiveInterval(LiveInterval* LI);
+ VNInfo* PerformPHIConstruction(MachineBasicBlock::iterator use,
+ MachineBasicBlock* MBB,
+ LiveInterval* LI,
+ SmallPtrSet<MachineInstr*, 4>& Visited,
+ DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Defs,
+ DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Uses,
+ DenseMap<MachineInstr*, VNInfo*>& NewVNs,
+ DenseMap<MachineBasicBlock*, VNInfo*>& LiveOut,
+ DenseMap<MachineBasicBlock*, VNInfo*>& Phis,
+ bool toplevel, bool intrablock);
+};
} // end anonymous namespace
char PreAllocSplitting::ID = 0;
/// none is found.
MachineBasicBlock::iterator
PreAllocSplitting::findSpillPoint(MachineBasicBlock *MBB, MachineInstr *MI,
+ MachineInstr *DefMI,
SmallPtrSet<MachineInstr*, 4> &RefsInMBB,
unsigned &SpillIndex) {
MachineBasicBlock::iterator Pt = MBB->begin();
// Go top down if RefsInMBB is empty.
- if (RefsInMBB.empty()) {
+ if (RefsInMBB.empty() && !DefMI) {
MachineBasicBlock::iterator MII = MBB->begin();
MachineBasicBlock::iterator EndPt = MI;
do {
} while (MII != EndPt);
} else {
MachineBasicBlock::iterator MII = MI;
- while (MII != MBB->begin() && !RefsInMBB.count(MII)) {
+ MachineBasicBlock::iterator EndPt = DefMI
+ ? MachineBasicBlock::iterator(DefMI) : MBB->begin();
+ while (MII != EndPt && !RefsInMBB.count(MII)) {
unsigned Index = LIs->getInstructionIndex(MII);
if (LIs->hasGapBeforeInstr(Index)) {
Pt = MII;
/// found.
MachineBasicBlock::iterator
PreAllocSplitting::findRestorePoint(MachineBasicBlock *MBB, MachineInstr *MI,
+ unsigned LastIdx,
SmallPtrSet<MachineInstr*, 4> &RefsInMBB,
unsigned &RestoreIndex) {
+ // FIXME: Allow spill to be inserted to the beginning of the mbb. Update mbb
+ // begin index accordingly.
MachineBasicBlock::iterator Pt = MBB->end();
+ unsigned EndIdx = LIs->getMBBEndIdx(MBB);
- // Go bottom up if RefsInMBB is empty.
- if (RefsInMBB.empty()) {
- MachineBasicBlock::iterator MII = MBB->end();
+ // Go bottom up if RefsInMBB is empty and the end of the mbb isn't beyond
+ // the last index in the live range.
+ if (RefsInMBB.empty() && LastIdx >= EndIdx) {
+ MachineBasicBlock::iterator MII = MBB->getFirstTerminator();
MachineBasicBlock::iterator EndPt = MI;
+ --MII;
do {
- --MII;
unsigned Index = LIs->getInstructionIndex(MII);
unsigned Gap = LIs->findGapBeforeInstr(Index);
if (Gap) {
RestoreIndex = Gap;
break;
}
+ --MII;
} while (MII != EndPt);
} else {
MachineBasicBlock::iterator MII = MI;
MII = ++MII;
+ // FIXME: Limit the number of instructions to examine to reduce
+ // compile time?
while (MII != MBB->end()) {
unsigned Index = LIs->getInstructionIndex(MII);
+ if (Index > LastIdx)
+ break;
unsigned Gap = LIs->findGapBeforeInstr(Index);
if (Gap) {
Pt = MII;
return Pt;
}
-/// RecordSplit - Given a register live interval is split, remember the spill
-/// slot where the val#s are in.
-void PreAllocSplitting::RecordSplit(unsigned Reg, unsigned SpillIndex,
- unsigned RestoreIndex, int SS) {
- const LiveRange *LR = NULL;
- if (SpillIndex) {
- LR = CurrLI->getLiveRangeContaining(LIs->getUseIndex(SpillIndex));
- LIValNoSSMap.insert(std::make_pair(std::make_pair(CurrLI->reg,
- LR->valno->id), SS));
- }
- LR = CurrLI->getLiveRangeContaining(LIs->getDefIndex(RestoreIndex));
- LIValNoSSMap.insert(std::make_pair(std::make_pair(CurrLI->reg,
- LR->valno->id), SS));
+/// CreateSpillStackSlot - Create a stack slot for the live interval being
+/// split. If the live interval was previously split, just reuse the same
+/// slot.
+int PreAllocSplitting::CreateSpillStackSlot(unsigned Reg,
+ const TargetRegisterClass *RC) {
+ int SS;
+ DenseMap<unsigned, int>::iterator I = IntervalSSMap.find(Reg);
+ if (I != IntervalSSMap.end()) {
+ SS = I->second;
+ } else {
+ SS = MFI->CreateStackObject(RC->getSize(), RC->getAlignment());
+ IntervalSSMap[Reg] = SS;
+ }
+
+ // Create live interval for stack slot.
+ CurrSLI = &LSs->getOrCreateInterval(SS);
+ if (CurrSLI->hasAtLeastOneValue())
+ CurrSValNo = CurrSLI->getValNumInfo(0);
+ else
+ CurrSValNo = CurrSLI->getNextValue(~0U, 0, LSs->getVNInfoAllocator());
+ return SS;
}
-/// isAlreadySplit - Return if a given val# of a register live interval is already
-/// split. Also return by reference the spill stock where the value is.
-bool PreAllocSplitting::isAlreadySplit(unsigned Reg, unsigned ValNoId, int &SS){
- std::map<std::pair<unsigned, unsigned>, int>::iterator I =
- LIValNoSSMap.find(std::make_pair(Reg, ValNoId));
- if (I == LIValNoSSMap.end())
+/// IsAvailableInStack - Return true if register is available in a split stack
+/// slot at the specified index.
+bool
+PreAllocSplitting::IsAvailableInStack(MachineBasicBlock *DefMBB,
+ unsigned Reg, unsigned DefIndex,
+ unsigned RestoreIndex, unsigned &SpillIndex,
+ int& SS) const {
+ if (!DefMBB)
+ return false;
+
+ DenseMap<unsigned, int>::iterator I = IntervalSSMap.find(Reg);
+ if (I == IntervalSSMap.end())
return false;
+ DenseMap<unsigned, unsigned>::iterator II = Def2SpillMap.find(DefIndex);
+ if (II == Def2SpillMap.end())
+ return false;
+
+ // If last spill of def is in the same mbb as barrier mbb (where restore will
+ // be), make sure it's not below the intended restore index.
+ // FIXME: Undo the previous spill?
+ assert(LIs->getMBBFromIndex(II->second) == DefMBB);
+ if (DefMBB == BarrierMBB && II->second >= RestoreIndex)
+ return false;
+
SS = I->second;
+ SpillIndex = II->second;
return true;
}
-/// UpdateIntervalForSplit - Given the specified val# of the current live
-/// interval is being split, and the split and rejoin indices, update the live
-/// interval accordingly.
+/// UpdateSpillSlotInterval - Given the specified val# of the register live
+/// interval being split, and the spill and restore indicies, update the live
+/// interval of the spill stack slot.
void
-PreAllocSplitting::UpdateIntervalForSplit(VNInfo *ValNo, unsigned SplitIndex,
- unsigned JoinIndex) {
+PreAllocSplitting::UpdateSpillSlotInterval(VNInfo *ValNo, unsigned SpillIndex,
+ unsigned RestoreIndex) {
+ assert(LIs->getMBBFromIndex(RestoreIndex) == BarrierMBB &&
+ "Expect restore in the barrier mbb");
+
+ MachineBasicBlock *MBB = LIs->getMBBFromIndex(SpillIndex);
+ if (MBB == BarrierMBB) {
+ // Intra-block spill + restore. We are done.
+ LiveRange SLR(SpillIndex, RestoreIndex, CurrSValNo);
+ CurrSLI->addRange(SLR);
+ return;
+ }
+
+ SmallPtrSet<MachineBasicBlock*, 4> Processed;
+ unsigned EndIdx = LIs->getMBBEndIdx(MBB);
+ LiveRange SLR(SpillIndex, EndIdx+1, CurrSValNo);
+ CurrSLI->addRange(SLR);
+ Processed.insert(MBB);
+
+ // Start from the spill mbb, figure out the extend of the spill slot's
+ // live interval.
+ SmallVector<MachineBasicBlock*, 4> WorkList;
+ const LiveRange *LR = CurrLI->getLiveRangeContaining(SpillIndex);
+ if (LR->end > EndIdx)
+ // If live range extend beyond end of mbb, add successors to work list.
+ for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
+ SE = MBB->succ_end(); SI != SE; ++SI)
+ WorkList.push_back(*SI);
+
+ while (!WorkList.empty()) {
+ MachineBasicBlock *MBB = WorkList.back();
+ WorkList.pop_back();
+ if (Processed.count(MBB))
+ continue;
+ unsigned Idx = LIs->getMBBStartIdx(MBB);
+ LR = CurrLI->getLiveRangeContaining(Idx);
+ if (LR && LR->valno == ValNo) {
+ EndIdx = LIs->getMBBEndIdx(MBB);
+ if (Idx <= RestoreIndex && RestoreIndex < EndIdx) {
+ // Spill slot live interval stops at the restore.
+ LiveRange SLR(Idx, RestoreIndex, CurrSValNo);
+ CurrSLI->addRange(SLR);
+ } else if (LR->end > EndIdx) {
+ // Live range extends beyond end of mbb, process successors.
+ LiveRange SLR(Idx, EndIdx+1, CurrSValNo);
+ CurrSLI->addRange(SLR);
+ for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
+ SE = MBB->succ_end(); SI != SE; ++SI)
+ WorkList.push_back(*SI);
+ } else {
+ LiveRange SLR(Idx, LR->end, CurrSValNo);
+ CurrSLI->addRange(SLR);
+ }
+ Processed.insert(MBB);
+ }
+ }
+}
+
+/// UpdateRegisterInterval - Given the specified val# of the current live
+/// interval is being split, and the spill and restore indices, update the live
+/// interval accordingly.
+VNInfo*
+PreAllocSplitting::UpdateRegisterInterval(VNInfo *ValNo, unsigned SpillIndex,
+ unsigned RestoreIndex) {
+ assert(LIs->getMBBFromIndex(RestoreIndex) == BarrierMBB &&
+ "Expect restore in the barrier mbb");
+
SmallVector<std::pair<unsigned,unsigned>, 4> Before;
SmallVector<std::pair<unsigned,unsigned>, 4> After;
SmallVector<unsigned, 4> BeforeKills;
// First, let's figure out which parts of the live interval is now defined
// by the restore, which are defined by the original definition.
- const LiveRange *LR = CurrLI->getLiveRangeContaining(JoinIndex);
- After.push_back(std::make_pair(JoinIndex, LR->end));
+ const LiveRange *LR = CurrLI->getLiveRangeContaining(RestoreIndex);
+ After.push_back(std::make_pair(RestoreIndex, LR->end));
if (CurrLI->isKill(ValNo, LR->end))
AfterKills.push_back(LR->end);
- assert(LR->contains(SplitIndex));
- if (SplitIndex > LR->start) {
- Before.push_back(std::make_pair(LR->start, SplitIndex));
- BeforeKills.push_back(SplitIndex);
+ assert(LR->contains(SpillIndex));
+ if (SpillIndex > LR->start) {
+ Before.push_back(std::make_pair(LR->start, SpillIndex));
+ BeforeKills.push_back(SpillIndex);
}
Processed.insert(LR);
+ // Start from the restore mbb, figure out what part of the live interval
+ // are defined by the restore.
SmallVector<MachineBasicBlock*, 4> WorkList;
- MachineBasicBlock *MBB = LIs->getMBBFromIndex(LR->end-1);
+ MachineBasicBlock *MBB = BarrierMBB;
for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
SE = MBB->succ_end(); SI != SE; ++SI)
WorkList.push_back(*SI);
+ SmallPtrSet<MachineBasicBlock*, 4> ProcessedBlocks;
+ ProcessedBlocks.insert(MBB);
+
while (!WorkList.empty()) {
MBB = WorkList.back();
WorkList.pop_back();
AfterKills.push_back(LR->end);
Idx = LIs->getMBBEndIdx(MBB);
if (LR->end > Idx) {
- for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI)
- WorkList.push_back(*SI);
- if (LR->end > Idx+1) {
- MBB = LIs->getMBBFromIndex(LR->end-1);
- for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI)
- WorkList.push_back(*SI);
- }
+ // Live range extend beyond at least one mbb. Let's see what other
+ // mbbs it reaches.
+ LIs->findReachableMBBs(LR->start, LR->end, WorkList);
}
Processed.insert(LR);
}
+
+ ProcessedBlocks.insert(MBB);
+ if (LR)
+ for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
+ SE = MBB->succ_end(); SI != SE; ++SI)
+ if (!ProcessedBlocks.count(*SI))
+ WorkList.push_back(*SI);
}
for (LiveInterval::iterator I = CurrLI->begin(), E = CurrLI->end();
VNInfo *AValNo = (After.empty())
? NULL
- : CurrLI->getNextValue(JoinIndex,0, LIs->getVNInfoAllocator());
+ : CurrLI->getNextValue(RestoreIndex, 0, LIs->getVNInfoAllocator());
if (AValNo) {
AValNo->hasPHIKill = HasPHIKill;
CurrLI->addKills(AValNo, AfterKills);
unsigned End = After[i].second;
CurrLI->addRange(LiveRange(Start, End, AValNo));
}
+
+ return AValNo;
}
/// ShrinkWrapToLastUse - There are uses of the current live interval in the
/// from last use to the end of the mbb). In case mbb is the where the barrier
/// is, remove from the last use to the barrier.
bool
-PreAllocSplitting::ShrinkWrapToLastUse(MachineBasicBlock *MBB,
+PreAllocSplitting::ShrinkWrapToLastUse(MachineBasicBlock *MBB, VNInfo *ValNo,
SmallVector<MachineOperand*, 4> &Uses,
SmallPtrSet<MachineInstr*, 4> &UseMIs) {
MachineOperand *LastMO = 0;
MII = Barrier;
else
MII = MBB->end();
- while (--MII != MEE) {
+ while (MII != MEE) {
+ --MII;
MachineInstr *UseMI = &*MII;
if (!UseMIs.count(UseMI))
continue;
if (MBB == BarrierMBB)
RangeEnd = LIs->getUseIndex(BarrierIdx)+1;
CurrLI->removeRange(RangeStart, RangeEnd);
+ if (LastMI)
+ CurrLI->addKill(ValNo, RangeStart);
// Return true if the last use becomes a new kill.
return LastMI;
}
+/// PerformPHIConstruction - From properly set up use and def lists, use a PHI
+/// construction algorithm to compute the ranges and valnos for an interval.
+VNInfo* PreAllocSplitting::PerformPHIConstruction(
+ MachineBasicBlock::iterator use,
+ MachineBasicBlock* MBB,
+ LiveInterval* LI,
+ SmallPtrSet<MachineInstr*, 4>& Visited,
+ DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Defs,
+ DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Uses,
+ DenseMap<MachineInstr*, VNInfo*>& NewVNs,
+ DenseMap<MachineBasicBlock*, VNInfo*>& LiveOut,
+ DenseMap<MachineBasicBlock*, VNInfo*>& Phis,
+ bool toplevel, bool intrablock) {
+ // Return memoized result if it's available.
+ if (toplevel && Visited.count(use) && NewVNs.count(use))
+ return NewVNs[use];
+ else if (!toplevel && intrablock && NewVNs.count(use))
+ return NewVNs[use];
+ else if (!intrablock && LiveOut.count(MBB))
+ return LiveOut[MBB];
+
+ typedef DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> > RegMap;
+
+ // Check if our block contains any uses or defs.
+ bool ContainsDefs = Defs.count(MBB);
+ bool ContainsUses = Uses.count(MBB);
+
+ VNInfo* ret = 0;
+
+ // Enumerate the cases of use/def contaning blocks.
+ if (!ContainsDefs && !ContainsUses) {
+ Fallback:
+ // NOTE: Because this is the fallback case from other cases, we do NOT
+ // assume that we are not intrablock here.
+ if (Phis.count(MBB)) return Phis[MBB];
+
+ unsigned StartIndex = LIs->getMBBStartIdx(MBB);
+
+ if (MBB->pred_size() == 1) {
+ Phis[MBB] = ret = PerformPHIConstruction((*MBB->pred_begin())->end(),
+ *(MBB->pred_begin()), LI, Visited,
+ Defs, Uses, NewVNs, LiveOut, Phis,
+ false, false);
+ unsigned EndIndex = 0;
+ if (intrablock) {
+ EndIndex = LIs->getInstructionIndex(use);
+ EndIndex = LiveIntervals::getUseIndex(EndIndex);
+ } else
+ EndIndex = LIs->getMBBEndIdx(MBB);
+
+ LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
+ if (intrablock)
+ LI->addKill(ret, EndIndex);
+ } else {
+ Phis[MBB] = ret = LI->getNextValue(~0U, /*FIXME*/ 0,
+ LIs->getVNInfoAllocator());
+ if (!intrablock) LiveOut[MBB] = ret;
+
+ // If there are no uses or defs between our starting point and the
+ // beginning of the block, then recursive perform phi construction
+ // on our predecessors.
+ DenseMap<MachineBasicBlock*, VNInfo*> IncomingVNs;
+ for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
+ PE = MBB->pred_end(); PI != PE; ++PI) {
+ VNInfo* Incoming = PerformPHIConstruction((*PI)->end(), *PI, LI,
+ Visited, Defs, Uses, NewVNs,
+ LiveOut, Phis, false, false);
+ if (Incoming != 0)
+ IncomingVNs[*PI] = Incoming;
+ }
+
+ // Otherwise, merge the incoming VNInfos with a phi join. Create a new
+ // VNInfo to represent the joined value.
+ for (DenseMap<MachineBasicBlock*, VNInfo*>::iterator I =
+ IncomingVNs.begin(), E = IncomingVNs.end(); I != E; ++I) {
+ I->second->hasPHIKill = true;
+ unsigned KillIndex = LIs->getMBBEndIdx(I->first);
+ LI->addKill(I->second, KillIndex);
+ }
+
+ unsigned EndIndex = 0;
+ if (intrablock) {
+ EndIndex = LIs->getInstructionIndex(use);
+ EndIndex = LiveIntervals::getUseIndex(EndIndex);
+ } else
+ EndIndex = LIs->getMBBEndIdx(MBB);
+ LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
+ if (intrablock)
+ LI->addKill(ret, EndIndex);
+ }
+ } else if (ContainsDefs && !ContainsUses) {
+ SmallPtrSet<MachineInstr*, 2>& BlockDefs = Defs[MBB];
+
+ // Search for the def in this block. If we don't find it before the
+ // instruction we care about, go to the fallback case. Note that that
+ // should never happen: this cannot be intrablock, so use should
+ // always be an end() iterator.
+ assert(use == MBB->end() && "No use marked in intrablock");
+
+ MachineBasicBlock::iterator walker = use;
+ --walker;
+ while (walker != MBB->begin())
+ if (BlockDefs.count(walker)) {
+ break;
+ } else
+ --walker;
+
+ // Once we've found it, extend its VNInfo to our instruction.
+ unsigned DefIndex = LIs->getInstructionIndex(walker);
+ DefIndex = LiveIntervals::getDefIndex(DefIndex);
+ unsigned EndIndex = LIs->getMBBEndIdx(MBB);
+
+ ret = NewVNs[walker];
+ LI->addRange(LiveRange(DefIndex, EndIndex+1, ret));
+ } else if (!ContainsDefs && ContainsUses) {
+ SmallPtrSet<MachineInstr*, 2>& BlockUses = Uses[MBB];
+
+ // Search for the use in this block that precedes the instruction we care
+ // about, going to the fallback case if we don't find it.
+
+ if (use == MBB->begin())
+ goto Fallback;
+
+ MachineBasicBlock::iterator walker = use;
+ --walker;
+ bool found = false;
+ while (walker != MBB->begin())
+ if (BlockUses.count(walker)) {
+ found = true;
+ break;
+ } else
+ --walker;
+
+ // Must check begin() too.
+ if (!found) {
+ if (BlockUses.count(walker))
+ found = true;
+ else
+ goto Fallback;
+ }
+
+ unsigned UseIndex = LIs->getInstructionIndex(walker);
+ UseIndex = LiveIntervals::getUseIndex(UseIndex);
+ unsigned EndIndex = 0;
+ if (intrablock) {
+ EndIndex = LIs->getInstructionIndex(use);
+ EndIndex = LiveIntervals::getUseIndex(EndIndex);
+ } else
+ EndIndex = LIs->getMBBEndIdx(MBB);
+
+ // Now, recursively phi construct the VNInfo for the use we found,
+ // and then extend it to include the instruction we care about
+ ret = PerformPHIConstruction(walker, MBB, LI, Visited, Defs, Uses,
+ NewVNs, LiveOut, Phis, false, true);
+
+ // FIXME: Need to set kills properly for inter-block stuff.
+ if (LI->isKill(ret, UseIndex)) LI->removeKill(ret, UseIndex);
+ if (intrablock)
+ LI->addKill(ret, EndIndex);
+
+ LI->addRange(LiveRange(UseIndex, EndIndex+1, ret));
+ } else if (ContainsDefs && ContainsUses){
+ SmallPtrSet<MachineInstr*, 2>& BlockDefs = Defs[MBB];
+ SmallPtrSet<MachineInstr*, 2>& BlockUses = Uses[MBB];
+
+ // This case is basically a merging of the two preceding case, with the
+ // special note that checking for defs must take precedence over checking
+ // for uses, because of two-address instructions.
+
+ if (use == MBB->begin())
+ goto Fallback;
+
+ MachineBasicBlock::iterator walker = use;
+ --walker;
+ bool foundDef = false;
+ bool foundUse = false;
+ while (walker != MBB->begin())
+ if (BlockDefs.count(walker)) {
+ foundDef = true;
+ break;
+ } else if (BlockUses.count(walker)) {
+ foundUse = true;
+ break;
+ } else
+ --walker;
+
+ // Must check begin() too.
+ if (!foundDef && !foundUse) {
+ if (BlockDefs.count(walker))
+ foundDef = true;
+ else if (BlockUses.count(walker))
+ foundUse = true;
+ else
+ goto Fallback;
+ }
+
+ unsigned StartIndex = LIs->getInstructionIndex(walker);
+ StartIndex = foundDef ? LiveIntervals::getDefIndex(StartIndex) :
+ LiveIntervals::getUseIndex(StartIndex);
+ unsigned EndIndex = 0;
+ if (intrablock) {
+ EndIndex = LIs->getInstructionIndex(use);
+ EndIndex = LiveIntervals::getUseIndex(EndIndex);
+ } else
+ EndIndex = LIs->getMBBEndIdx(MBB);
+
+ if (foundDef)
+ ret = NewVNs[walker];
+ else
+ ret = PerformPHIConstruction(walker, MBB, LI, Visited, Defs, Uses,
+ NewVNs, LiveOut, Phis, false, true);
+
+ if (foundUse && LI->isKill(ret, StartIndex))
+ LI->removeKill(ret, StartIndex);
+ if (intrablock) {
+ LI->addKill(ret, EndIndex);
+ }
+
+ LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
+ }
+
+ // Memoize results so we don't have to recompute them.
+ if (!intrablock) LiveOut[MBB] = ret;
+ else {
+ if (!NewVNs.count(use))
+ NewVNs[use] = ret;
+ Visited.insert(use);
+ }
+
+ return ret;
+}
+
+/// ReconstructLiveInterval - Recompute a live interval from scratch.
+void PreAllocSplitting::ReconstructLiveInterval(LiveInterval* LI) {
+ BumpPtrAllocator& Alloc = LIs->getVNInfoAllocator();
+
+ // Clear the old ranges and valnos;
+ LI->clear();
+
+ // Cache the uses and defs of the register
+ typedef DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> > RegMap;
+ RegMap Defs, Uses;
+
+ // Keep track of the new VNs we're creating.
+ DenseMap<MachineInstr*, VNInfo*> NewVNs;
+ SmallPtrSet<VNInfo*, 2> PhiVNs;
+
+ // Cache defs, and create a new VNInfo for each def.
+ for (MachineRegisterInfo::def_iterator DI = MRI->def_begin(LI->reg),
+ DE = MRI->def_end(); DI != DE; ++DI) {
+ Defs[(*DI).getParent()].insert(&*DI);
+
+ unsigned DefIdx = LIs->getInstructionIndex(&*DI);
+ DefIdx = LiveIntervals::getDefIndex(DefIdx);
+
+ VNInfo* NewVN = LI->getNextValue(DefIdx, 0, Alloc);
+
+ // If the def is a move, set the copy field.
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
+ if (TII->isMoveInstr(*DI, SrcReg, DstReg, SrcSubIdx, DstSubIdx))
+ if (DstReg == LI->reg)
+ NewVN->copy = &*DI;
+
+ NewVNs[&*DI] = NewVN;
+ }
+
+ // Cache uses as a separate pass from actually processing them.
+ for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(LI->reg),
+ UE = MRI->use_end(); UI != UE; ++UI)
+ Uses[(*UI).getParent()].insert(&*UI);
+
+ // Now, actually process every use and use a phi construction algorithm
+ // to walk from it to its reaching definitions, building VNInfos along
+ // the way.
+ DenseMap<MachineBasicBlock*, VNInfo*> LiveOut;
+ DenseMap<MachineBasicBlock*, VNInfo*> Phis;
+ SmallPtrSet<MachineInstr*, 4> Visited;
+ for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(LI->reg),
+ UE = MRI->use_end(); UI != UE; ++UI) {
+ PerformPHIConstruction(&*UI, UI->getParent(), LI, Visited, Defs,
+ Uses, NewVNs, LiveOut, Phis, true, true);
+ }
+
+ // Add ranges for dead defs
+ for (MachineRegisterInfo::def_iterator DI = MRI->def_begin(LI->reg),
+ DE = MRI->def_end(); DI != DE; ++DI) {
+ unsigned DefIdx = LIs->getInstructionIndex(&*DI);
+ DefIdx = LiveIntervals::getDefIndex(DefIdx);
+
+ if (LI->liveAt(DefIdx)) continue;
+
+ VNInfo* DeadVN = NewVNs[&*DI];
+ LI->addRange(LiveRange(DefIdx, DefIdx+1, DeadVN));
+ LI->addKill(DeadVN, DefIdx);
+ }
+}
+
/// ShrinkWrapLiveInterval - Recursively traverse the predecessor
/// chain to find the new 'kills' and shrink wrap the live interval to the
/// new kill indices.
// If live interval is live in another successor path, then we can't process
// this block. But we may able to do so after all the successors have been
// processed.
- for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI) {
- MachineBasicBlock *SMBB = *SI;
- if (SMBB == SuccMBB)
- continue;
- if (CurrLI->liveAt(LIs->getMBBStartIdx(SMBB)))
- return;
+ if (MBB != BarrierMBB) {
+ for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
+ SE = MBB->succ_end(); SI != SE; ++SI) {
+ MachineBasicBlock *SMBB = *SI;
+ if (SMBB == SuccMBB)
+ continue;
+ if (CurrLI->liveAt(LIs->getMBBStartIdx(SMBB)))
+ return;
+ }
}
Visited.insert(MBB);
// At least one use in this mbb, lets look for the kill.
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >::iterator
UMII2 = UseMIs.find(MBB);
- if (ShrinkWrapToLastUse(MBB, UMII->second, UMII2->second))
+ if (ShrinkWrapToLastUse(MBB, ValNo, UMII->second, UMII2->second))
// Found a kill, shrink wrapping of this path ends here.
return;
} else if (MBB == DefMBB) {
- assert(LIValNoSSMap.find(std::make_pair(CurrLI->reg, ValNo->id)) !=
- LIValNoSSMap.end() && "Why wasn't def spilled?");
// There are no uses after the def.
MachineInstr *DefMI = LIs->getInstructionFromIndex(ValNo->def);
- assert(RestoreMIs.count(DefMI) && "Not defined by a join?");
if (UseMBBs.empty()) {
// The only use must be below barrier in the barrier block. It's safe to
// remove the def.
// Pred is the def bb and the def reaches other val#s, we must
// allow the value to be live out of the bb.
continue;
+ if (!CurrLI->liveAt(LIs->getMBBEndIdx(Pred)-1))
+ return;
ShrinkWrapLiveInterval(ValNo, Pred, MBB, DefMBB, Visited,
Uses, UseMIs, UseMBBs);
}
return;
}
+
+void PreAllocSplitting::RepairLiveInterval(LiveInterval* CurrLI,
+ VNInfo* ValNo,
+ MachineInstr* DefMI,
+ unsigned RestoreIdx) {
+ // Shrink wrap the live interval by walking up the CFG and find the
+ // new kills.
+ // Now let's find all the uses of the val#.
+ DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> > Uses;
+ DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> > UseMIs;
+ SmallPtrSet<MachineBasicBlock*, 4> Seen;
+ SmallVector<MachineBasicBlock*, 4> UseMBBs;
+ for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(CurrLI->reg),
+ UE = MRI->use_end(); UI != UE; ++UI) {
+ MachineOperand &UseMO = UI.getOperand();
+ MachineInstr *UseMI = UseMO.getParent();
+ unsigned UseIdx = LIs->getInstructionIndex(UseMI);
+ LiveInterval::iterator ULR = CurrLI->FindLiveRangeContaining(UseIdx);
+ if (ULR->valno != ValNo)
+ continue;
+ MachineBasicBlock *UseMBB = UseMI->getParent();
+ // Remember which other mbb's use this val#.
+ if (Seen.insert(UseMBB) && UseMBB != BarrierMBB)
+ UseMBBs.push_back(UseMBB);
+ DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >::iterator
+ UMII = Uses.find(UseMBB);
+ if (UMII != Uses.end()) {
+ DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >::iterator
+ UMII2 = UseMIs.find(UseMBB);
+ UMII->second.push_back(&UseMO);
+ UMII2->second.insert(UseMI);
+ } else {
+ SmallVector<MachineOperand*, 4> Ops;
+ Ops.push_back(&UseMO);
+ Uses.insert(std::make_pair(UseMBB, Ops));
+ SmallPtrSet<MachineInstr*, 4> MIs;
+ MIs.insert(UseMI);
+ UseMIs.insert(std::make_pair(UseMBB, MIs));
+ }
+ }
+
+ // Walk up the predecessor chains.
+ SmallPtrSet<MachineBasicBlock*, 8> Visited;
+ ShrinkWrapLiveInterval(ValNo, BarrierMBB, NULL, DefMI->getParent(), Visited,
+ Uses, UseMIs, UseMBBs);
+
+ // Remove live range from barrier to the restore. FIXME: Find a better
+ // point to re-start the live interval.
+ VNInfo* AfterValNo = UpdateRegisterInterval(ValNo,
+ LIs->getUseIndex(BarrierIdx)+1,
+ LIs->getDefIndex(RestoreIdx));
+
+ // Attempt to renumber the new valno into a new vreg.
+ RenumberValno(AfterValNo);
+}
+
+/// RenumberValno - Split the given valno out into a new vreg, allowing it to
+/// be allocated to a different register. This function creates a new vreg,
+/// copies the valno and its live ranges over to the new vreg's interval,
+/// removes them from the old interval, and rewrites all uses and defs of
+/// the original reg to the new vreg within those ranges.
+void PreAllocSplitting::RenumberValno(VNInfo* VN) {
+ SmallVector<VNInfo*, 4> Stack;
+ SmallVector<VNInfo*, 4> VNsToCopy;
+ Stack.push_back(VN);
+
+ // Walk through and copy the valno we care about, and any other valnos
+ // that are two-address redefinitions of the one we care about. These
+ // will need to be rewritten as well. We also check for safety of the
+ // renumbering here, by making sure that none of the valno involved has
+ // phi kills.
+ while (!Stack.empty()) {
+ VNInfo* OldVN = Stack.back();
+ Stack.pop_back();
+
+ // Bail out if we ever encounter a valno that has a PHI kill. We can't
+ // renumber these.
+ if (OldVN->hasPHIKill) return;
+
+ VNsToCopy.push_back(OldVN);
+
+ // Locate two-address redefinitions
+ for (SmallVector<unsigned, 4>::iterator KI = OldVN->kills.begin(),
+ KE = OldVN->kills.end(); KI != KE; ++KI) {
+ MachineInstr* MI = LIs->getInstructionFromIndex(*KI);
+ //if (!MI) continue;
+ unsigned DefIdx = MI->findRegisterDefOperandIdx(CurrLI->reg);
+ if (DefIdx == ~0U) continue;
+ if (MI->isRegReDefinedByTwoAddr(DefIdx)) {
+ VNInfo* NextVN =
+ CurrLI->findDefinedVNInfo(LiveIntervals::getDefIndex(*KI));
+ Stack.push_back(NextVN);
+ }
+ }
+ }
+
+ // Create the new vreg
+ unsigned NewVReg = MRI->createVirtualRegister(MRI->getRegClass(CurrLI->reg));
+
+ // Create the new live interval
+ LiveInterval& NewLI = LIs->getOrCreateInterval(NewVReg);
+
+ for (SmallVector<VNInfo*, 4>::iterator OI = VNsToCopy.begin(), OE =
+ VNsToCopy.end(); OI != OE; ++OI) {
+ VNInfo* OldVN = *OI;
+
+ // Copy the valno over
+ VNInfo* NewVN = NewLI.getNextValue(OldVN->def, OldVN->copy,
+ LIs->getVNInfoAllocator());
+ NewLI.copyValNumInfo(NewVN, OldVN);
+ NewLI.MergeValueInAsValue(*CurrLI, OldVN, NewVN);
+
+ // Remove the valno from the old interval
+ CurrLI->removeValNo(OldVN);
+ }
+
+ // Rewrite defs and uses. This is done in two stages to avoid invalidating
+ // the reg_iterator.
+ SmallVector<std::pair<MachineInstr*, unsigned>, 8> OpsToChange;
+
+ for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(CurrLI->reg),
+ E = MRI->reg_end(); I != E; ++I) {
+ MachineOperand& MO = I.getOperand();
+ unsigned InstrIdx = LIs->getInstructionIndex(&*I);
+
+ if ((MO.isUse() && NewLI.liveAt(LiveIntervals::getUseIndex(InstrIdx))) ||
+ (MO.isDef() && NewLI.liveAt(LiveIntervals::getDefIndex(InstrIdx))))
+ OpsToChange.push_back(std::make_pair(&*I, I.getOperandNo()));
+ }
+
+ for (SmallVector<std::pair<MachineInstr*, unsigned>, 8>::iterator I =
+ OpsToChange.begin(), E = OpsToChange.end(); I != E; ++I) {
+ MachineInstr* Inst = I->first;
+ unsigned OpIdx = I->second;
+ MachineOperand& MO = Inst->getOperand(OpIdx);
+ MO.setReg(NewVReg);
+ }
+
+ NumRenumbers++;
+}
+
+bool PreAllocSplitting::Rematerialize(unsigned vreg, VNInfo* ValNo,
+ MachineInstr* DefMI,
+ MachineBasicBlock::iterator RestorePt,
+ unsigned RestoreIdx,
+ SmallPtrSet<MachineInstr*, 4>& RefsInMBB) {
+ MachineBasicBlock& MBB = *RestorePt->getParent();
+
+ MachineBasicBlock::iterator KillPt = BarrierMBB->end();
+ unsigned KillIdx = 0;
+ if (ValNo->def == ~0U || DefMI->getParent() == BarrierMBB)
+ KillPt = findSpillPoint(BarrierMBB, Barrier, NULL, RefsInMBB, KillIdx);
+ else
+ KillPt = findNextEmptySlot(DefMI->getParent(), DefMI, KillIdx);
+
+ if (KillPt == DefMI->getParent()->end())
+ return false;
+
+ TII->reMaterialize(MBB, RestorePt, vreg, DefMI);
+ LIs->InsertMachineInstrInMaps(prior(RestorePt), RestoreIdx);
+
+ if (KillPt->getParent() == BarrierMBB) {
+ VNInfo* After = UpdateRegisterInterval(ValNo, LIs->getUseIndex(KillIdx)+1,
+ LIs->getDefIndex(RestoreIdx));
+
+ RenumberValno(After);
+
+ ++NumSplits;
+ ++NumRemats;
+ return true;
+ }
+
+ RepairLiveInterval(CurrLI, ValNo, DefMI, RestoreIdx);
+
+ ++NumSplits;
+ ++NumRemats;
+ return true;
+}
+
+MachineInstr* PreAllocSplitting::FoldSpill(unsigned vreg,
+ const TargetRegisterClass* RC,
+ MachineInstr* DefMI,
+ MachineInstr* Barrier,
+ MachineBasicBlock* MBB,
+ int& SS,
+ SmallPtrSet<MachineInstr*, 4>& RefsInMBB) {
+ MachineBasicBlock::iterator Pt = MBB->begin();
+
+ // Go top down if RefsInMBB is empty.
+ if (RefsInMBB.empty())
+ return 0;
+
+ MachineBasicBlock::iterator FoldPt = Barrier;
+ while (&*FoldPt != DefMI && FoldPt != MBB->begin() &&
+ !RefsInMBB.count(FoldPt))
+ --FoldPt;
+
+ int OpIdx = FoldPt->findRegisterDefOperandIdx(vreg, false);
+ if (OpIdx == -1)
+ return 0;
+
+ SmallVector<unsigned, 1> Ops;
+ Ops.push_back(OpIdx);
+
+ if (!TII->canFoldMemoryOperand(FoldPt, Ops))
+ return 0;
+
+ DenseMap<unsigned, int>::iterator I = IntervalSSMap.find(vreg);
+ if (I != IntervalSSMap.end()) {
+ SS = I->second;
+ } else {
+ SS = MFI->CreateStackObject(RC->getSize(), RC->getAlignment());
+
+ }
+
+ MachineInstr* FMI = TII->foldMemoryOperand(*MBB->getParent(),
+ FoldPt, Ops, SS);
+
+ if (FMI) {
+ LIs->ReplaceMachineInstrInMaps(FoldPt, FMI);
+ FMI = MBB->insert(MBB->erase(FoldPt), FMI);
+ ++NumFolds;
+
+ IntervalSSMap[vreg] = SS;
+ CurrSLI = &LSs->getOrCreateInterval(SS);
+ if (CurrSLI->hasAtLeastOneValue())
+ CurrSValNo = CurrSLI->getValNumInfo(0);
+ else
+ CurrSValNo = CurrSLI->getNextValue(~0U, 0, LSs->getVNInfoAllocator());
+ }
+
+ return FMI;
+}
+
/// SplitRegLiveInterval - Split (spill and restore) the given live interval
/// so it would not cross the barrier that's being processed. Shrink wrap
/// (minimize) the live interval to the last uses.
abort();
}
- // FIXME: For now, if definition is rematerializable, do not split.
MachineInstr *DefMI = (ValNo->def != ~0U)
? LIs->getInstructionFromIndex(ValNo->def) : NULL;
- if (DefMI && LIs->isReMaterializable(*LI, ValNo, DefMI))
- return false;
// Find all references in the barrier mbb.
SmallPtrSet<MachineInstr*, 4> RefsInMBB;
// Find a point to restore the value after the barrier.
unsigned RestoreIndex;
MachineBasicBlock::iterator RestorePt =
- findRestorePoint(BarrierMBB, Barrier, RefsInMBB, RestoreIndex);
+ findRestorePoint(BarrierMBB, Barrier, LR->end, RefsInMBB, RestoreIndex);
if (RestorePt == BarrierMBB->end())
return false;
+ if (DefMI && LIs->isReMaterializable(*LI, ValNo, DefMI))
+ if (Rematerialize(LI->reg, ValNo, DefMI, RestorePt,
+ RestoreIndex, RefsInMBB))
+ return true;
+
// Add a spill either before the barrier or after the definition.
MachineBasicBlock *DefMBB = DefMI ? DefMI->getParent() : NULL;
const TargetRegisterClass *RC = MRI->getRegClass(CurrLI->reg);
- int SS;
unsigned SpillIndex = 0;
MachineInstr *SpillMI = NULL;
- bool PrevSpilled = isAlreadySplit(CurrLI->reg, ValNo->id, SS);
+ int SS = -1;
if (ValNo->def == ~0U) {
// If it's defined by a phi, we must split just before the barrier.
- MachineBasicBlock::iterator SpillPt =
- findSpillPoint(BarrierMBB, Barrier, RefsInMBB, SpillIndex);
- if (SpillPt == BarrierMBB->begin())
- return false; // No gap to insert spill.
- // Add spill.
- if (!PrevSpilled)
- // If previously split, reuse the spill slot.
- SS = MFI->CreateStackObject(RC->getSize(), RC->getAlignment());
- TII->storeRegToStackSlot(*BarrierMBB, SpillPt, CurrLI->reg, true, SS, RC);
- SpillMI = prior(SpillPt);
- LIs->InsertMachineInstrInMaps(SpillMI, SpillIndex);
- } else if (!PrevSpilled) {
- if (!DefMI)
- // Def is dead. Do nothing.
- return false;
+ if ((SpillMI = FoldSpill(LI->reg, RC, 0, Barrier,
+ BarrierMBB, SS, RefsInMBB))) {
+ SpillIndex = LIs->getInstructionIndex(SpillMI);
+ } else {
+ MachineBasicBlock::iterator SpillPt =
+ findSpillPoint(BarrierMBB, Barrier, NULL, RefsInMBB, SpillIndex);
+ if (SpillPt == BarrierMBB->begin())
+ return false; // No gap to insert spill.
+ // Add spill.
+
+ SS = CreateSpillStackSlot(CurrLI->reg, RC);
+ TII->storeRegToStackSlot(*BarrierMBB, SpillPt, CurrLI->reg, true, SS, RC);
+ SpillMI = prior(SpillPt);
+ LIs->InsertMachineInstrInMaps(SpillMI, SpillIndex);
+ }
+ } else if (!IsAvailableInStack(DefMBB, CurrLI->reg, ValNo->def,
+ RestoreIndex, SpillIndex, SS)) {
// If it's already split, just restore the value. There is no need to spill
// the def again.
- // Check if it's possible to insert a spill after the def MI.
- MachineBasicBlock::iterator SpillPt =
- findNextEmptySlot(DefMBB, DefMI, SpillIndex);
- if (SpillPt == DefMBB->end())
- return false; // No gap to insert spill.
- SS = MFI->CreateStackObject(RC->getSize(), RC->getAlignment());
-
- // Add spill. The store instruction kills the register if def is before
- // the barrier in the barrier block.
- TII->storeRegToStackSlot(*DefMBB, SpillPt, CurrLI->reg,
- DefMBB == BarrierMBB, SS, RC);
- SpillMI = prior(SpillPt);
- LIs->InsertMachineInstrInMaps(SpillMI, SpillIndex);
+ if (!DefMI)
+ return false; // Def is dead. Do nothing.
+
+ if ((SpillMI = FoldSpill(LI->reg, RC, DefMI, Barrier,
+ BarrierMBB, SS, RefsInMBB))) {
+ SpillIndex = LIs->getInstructionIndex(SpillMI);
+ } else {
+ // Check if it's possible to insert a spill after the def MI.
+ MachineBasicBlock::iterator SpillPt;
+ if (DefMBB == BarrierMBB) {
+ // Add spill after the def and the last use before the barrier.
+ SpillPt = findSpillPoint(BarrierMBB, Barrier, DefMI,
+ RefsInMBB, SpillIndex);
+ if (SpillPt == DefMBB->begin())
+ return false; // No gap to insert spill.
+ } else {
+ SpillPt = findNextEmptySlot(DefMBB, DefMI, SpillIndex);
+ if (SpillPt == DefMBB->end())
+ return false; // No gap to insert spill.
+ }
+ // Add spill. The store instruction kills the register if def is before
+ // the barrier in the barrier block.
+ SS = CreateSpillStackSlot(CurrLI->reg, RC);
+ TII->storeRegToStackSlot(*DefMBB, SpillPt, CurrLI->reg,
+ DefMBB == BarrierMBB, SS, RC);
+ SpillMI = prior(SpillPt);
+ LIs->InsertMachineInstrInMaps(SpillMI, SpillIndex);
+ }
}
+ // Remember def instruction index to spill index mapping.
+ if (DefMI && SpillMI)
+ Def2SpillMap[ValNo->def] = SpillIndex;
+
// Add restore.
- // FIXME: Create live interval for stack slot.
TII->loadRegFromStackSlot(*BarrierMBB, RestorePt, CurrLI->reg, SS, RC);
MachineInstr *LoadMI = prior(RestorePt);
LIs->InsertMachineInstrInMaps(LoadMI, RestoreIndex);
- RestoreMIs.insert(LoadMI);
// If live interval is spilled in the same block as the barrier, just
// create a hole in the interval.
if (!DefMBB ||
(SpillMI && SpillMI->getParent() == BarrierMBB)) {
- UpdateIntervalForSplit(ValNo, LIs->getUseIndex(SpillIndex)+1,
- LIs->getDefIndex(RestoreIndex));
+ // Update spill stack slot live interval.
+ UpdateSpillSlotInterval(ValNo, LIs->getUseIndex(SpillIndex)+1,
+ LIs->getDefIndex(RestoreIndex));
- // Record val# values are in the specific spill slot.
- RecordSplit(CurrLI->reg, SpillIndex, RestoreIndex, SS);
-
- ++NumSplit;
+ VNInfo* After = UpdateRegisterInterval(ValNo,
+ LIs->getUseIndex(SpillIndex)+1,
+ LIs->getDefIndex(RestoreIndex));
+ RenumberValno(After);
+
+ ++NumSplits;
return true;
}
- // Shrink wrap the live interval by walking up the CFG and find the
- // new kills.
- // Now let's find all the uses of the val#.
- DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> > Uses;
- DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> > UseMIs;
- SmallPtrSet<MachineBasicBlock*, 4> Seen;
- SmallVector<MachineBasicBlock*, 4> UseMBBs;
- for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(CurrLI->reg),
- UE = MRI->use_end(); UI != UE; ++UI) {
- MachineOperand &UseMO = UI.getOperand();
- MachineInstr *UseMI = UseMO.getParent();
- unsigned UseIdx = LIs->getInstructionIndex(UseMI);
- LiveInterval::iterator ULR = CurrLI->FindLiveRangeContaining(UseIdx);
- if (ULR->valno != ValNo)
- continue;
- MachineBasicBlock *UseMBB = UseMI->getParent();
- // Remember which other mbb's use this val#.
- if (Seen.insert(UseMBB) && UseMBB != BarrierMBB)
- UseMBBs.push_back(UseMBB);
- DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >::iterator
- UMII = Uses.find(UseMBB);
- if (UMII != Uses.end()) {
- DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >::iterator
- UMII2 = UseMIs.find(UseMBB);
- UMII->second.push_back(&UseMO);
- UMII2->second.insert(UseMI);
- } else {
- SmallVector<MachineOperand*, 4> Ops;
- Ops.push_back(&UseMO);
- Uses.insert(std::make_pair(UseMBB, Ops));
- SmallPtrSet<MachineInstr*, 4> MIs;
- MIs.insert(UseMI);
- UseMIs.insert(std::make_pair(UseMBB, MIs));
- }
- }
+ // Update spill stack slot live interval.
+ UpdateSpillSlotInterval(ValNo, LIs->getUseIndex(SpillIndex)+1,
+ LIs->getDefIndex(RestoreIndex));
- // Walk up the predecessor chains.
- SmallPtrSet<MachineBasicBlock*, 8> Visited;
- ShrinkWrapLiveInterval(ValNo, BarrierMBB, NULL, DefMBB, Visited,
- Uses, UseMIs, UseMBBs);
-
- // Remove live range from barrier to the restore. FIXME: Find a better
- // point to re-start the live interval.
- UpdateIntervalForSplit(ValNo, LIs->getUseIndex(BarrierIdx)+1,
- LIs->getDefIndex(RestoreIndex));
- // Record val# values are in the specific spill slot.
- RecordSplit(CurrLI->reg, SpillIndex, RestoreIndex, SS);
-
- ++NumSplit;
+ RepairLiveInterval(CurrLI, ValNo, DefMI, RestoreIndex);
+
+ ++NumSplits;
return true;
}
// Process the affected live intervals.
bool Change = false;
while (!Intervals.empty()) {
+ if (PreSplitLimit != -1 && (int)NumSplits == PreSplitLimit)
+ break;
+ else if (NumSplits == 4)
+ Change |= Change;
LiveInterval *LI = Intervals.back();
Intervals.pop_back();
Change |= SplitRegLiveInterval(LI);
return Change;
}
+bool PreAllocSplitting::createsNewJoin(LiveRange* LR,
+ MachineBasicBlock* DefMBB,
+ MachineBasicBlock* BarrierMBB) {
+ if (DefMBB == BarrierMBB)
+ return false;
+
+ if (LR->valno->hasPHIKill)
+ return false;
+
+ unsigned MBBEnd = LIs->getMBBEndIdx(BarrierMBB);
+ if (LR->end < MBBEnd)
+ return false;
+
+ MachineLoopInfo& MLI = getAnalysis<MachineLoopInfo>();
+ if (MLI.getLoopFor(DefMBB) != MLI.getLoopFor(BarrierMBB))
+ return true;
+
+ MachineDominatorTree& MDT = getAnalysis<MachineDominatorTree>();
+ SmallPtrSet<MachineBasicBlock*, 4> Visited;
+ typedef std::pair<MachineBasicBlock*,
+ MachineBasicBlock::succ_iterator> ItPair;
+ SmallVector<ItPair, 4> Stack;
+ Stack.push_back(std::make_pair(BarrierMBB, BarrierMBB->succ_begin()));
+
+ while (!Stack.empty()) {
+ ItPair P = Stack.back();
+ Stack.pop_back();
+
+ MachineBasicBlock* PredMBB = P.first;
+ MachineBasicBlock::succ_iterator S = P.second;
+
+ if (S == PredMBB->succ_end())
+ continue;
+ else if (Visited.count(*S)) {
+ Stack.push_back(std::make_pair(PredMBB, ++S));
+ continue;
+ } else
+ Stack.push_back(std::make_pair(PredMBB, S+1));
+
+ MachineBasicBlock* MBB = *S;
+ Visited.insert(MBB);
+
+ if (MBB == BarrierMBB)
+ return true;
+
+ MachineDomTreeNode* DefMDTN = MDT.getNode(DefMBB);
+ MachineDomTreeNode* BarrierMDTN = MDT.getNode(BarrierMBB);
+ MachineDomTreeNode* MDTN = MDT.getNode(MBB)->getIDom();
+ while (MDTN) {
+ if (MDTN == DefMDTN)
+ return true;
+ else if (MDTN == BarrierMDTN)
+ break;
+ MDTN = MDTN->getIDom();
+ }
+
+ MBBEnd = LIs->getMBBEndIdx(MBB);
+ if (LR->end > MBBEnd)
+ Stack.push_back(std::make_pair(MBB, MBB->succ_begin()));
+ }
+
+ return false;
+}
+
+
bool PreAllocSplitting::runOnMachineFunction(MachineFunction &MF) {
- CurMF = &MF;
- TM = &MF.getTarget();
- TII = TM->getInstrInfo();
- MFI = MF.getFrameInfo();
- MRI = &MF.getRegInfo();
- LIs = &getAnalysis<LiveIntervals>();
+ CurrMF = &MF;
+ TM = &MF.getTarget();
+ TII = TM->getInstrInfo();
+ MFI = MF.getFrameInfo();
+ MRI = &MF.getRegInfo();
+ LIs = &getAnalysis<LiveIntervals>();
+ LSs = &getAnalysis<LiveStacks>();
bool MadeChange = false;
// Make sure blocks are numbered in order.
MF.RenumberBlocks();
- for (MachineFunction::reverse_iterator I = MF.rbegin(), E = MF.rend();
- I != E; ++I) {
- BarrierMBB = &*I;
- for (MachineBasicBlock::reverse_iterator II = BarrierMBB->rbegin(),
- EE = BarrierMBB->rend(); II != EE; ++II) {
- Barrier = &*II;
+ MachineBasicBlock *Entry = MF.begin();
+ SmallPtrSet<MachineBasicBlock*,16> Visited;
+
+ for (df_ext_iterator<MachineBasicBlock*, SmallPtrSet<MachineBasicBlock*,16> >
+ DFI = df_ext_begin(Entry, Visited), E = df_ext_end(Entry, Visited);
+ DFI != E; ++DFI) {
+ BarrierMBB = *DFI;
+ for (MachineBasicBlock::iterator I = BarrierMBB->begin(),
+ E = BarrierMBB->end(); I != E; ++I) {
+ Barrier = &*I;
const TargetRegisterClass **BarrierRCs =
Barrier->getDesc().getRegClassBarriers();
if (!BarrierRCs)
projects / oota-llvm.git / blobdiff